The present treatment of insulin dependent diabetes mellitus (Type I) leaves much to be desired. As a result, most diabetic patients are rarely, if ever, normoglycemic during the entire day. For this reason the most important question which relates to the care of diabetic patients remains unanswered. That question is whether or not the level of diabetic control is related in any cause or effect way to the development of the microvascular complications of diabetes. With the recent development of portable insulin infusion pumps which deliver insulin continuously, it is now possible to provide near normal glucoregulation for long periods of time. These pumps are complicated and expensive and there is no definitive evidence to suggest that they would be superior to conventional methods of treatment with respect to the development and/or progression of microvascular complication. This research project is designed to evaluate the effectiveness of these portable insulin infusion systems in the long term use in and of themselves and in comparison to insulin given by multiple injections as well as to begin to evaluate the effect of rigid diabetic control on the development and/or progression of diabetic microvascular complications.